A. Field of Invention
This invention generally relates to devices and methods for converting mechanical energy into electrical energy. Some embodiments relate to piezoelectric devices.
B. Description of the Related Art
Devices for converting mechanical energy into electrical energy are well known in the art, e.g. antique hand-crank telephones. In the mid twentieth century vibrational energy harvesting devices (i.e. piezoelectric devices) were shown to be useful energy transducers. In one well known design a piezoelectric ceramic material is bonded to a cantilever beam to generate a voltage when the beam is deflected. Similar vibrating beam generators have been used to power sensors and wireless transmitters, replacing batteries in some cases. Existing devices can be less than optimum due to inefficient coupling between the mechanical vibrational energy input and the resonant frequencies of the piezoelectric element. Therefore there is a need in the art for a piezoelectric device that is capable of more efficiently harvesting mechanical energy from a wider range of vibrational modes.